Pacific System (PTWS)

Intergovernmental Coordination Group for the Pacific Tsunami Warning and Mitigation System (ICG/PTWS)


Click here to download PTWS Brochure

TsunamiWarningMap 20140226 Final
Click image above to download as PDF to zoom in.
Image: Existing Services of the Global Tsunami Warning System
Produced by the Intergovernmental Oceanographic Commission of UNESCO (
Feb. 13, 2014).

Under the auspices of the Intergovernmental Oceanographic Commission (IOC), the Intergovernmental Coordination Group for the Pacific Tsunami Warning and Mitigation System first convened in 1968 (ICG/PTWS, formerly known as ICG/ITSU for International Tsunami).  An international cooperative effort involving many Member States of the Pacific Region, ICG/PTWS meets regularly to review progress and coordinate activities resulting in improvements of the service. 

The PTWS area of responsibility includes the Pacific Ocean, the Southern Ocean regions of the Pacific and all attached marginal seas, including the Philippine Sea, East China Sea, Yellow Sea, Sea of Okhotsk, Bering Sea, South China Sea, Java Sea, Arafura Sea, Sulawesi Sea, Mindanao Sea, Sulu Sea, Celebes Sea, Bismarck Sea, Solomon Sea, Coral Sea, and Tasman Sea.

Altogether, there are 46 Member States covering the Pacific and its marginal seas. Official Member States of the ICG/PTWS are those who are members of UNESCO and the IOC, and who have officially designated Tsunami National Contacts and Tsunami Warning Focal Points through formal channels.

PTWS MEMBER STATES: 46 (53 countries and sub-jurisdictions)

All countries, except Democratic Republic of Korea, have provided Tsunami Warning Focal Point and Tsunami National Contact information. Cambodia, Federated States of Micronesia, Marshall Islands, Nauru, and Tokelau are Associate Member States of the IOC.

ICG/PTWS Member States with formal official designations (bold): 25
Member States that are not IOC Member States marked with *: 4
Member States with no recent information marked with +: 1

Brunei Darusalaam, Cambodia *, Canada, Chileincluding Easter Island and Juan Fernandez Islands, China - mainland, Hong Kong, Macau, Colombia, Costa Rica, Democratic Republic of Korea +, Ecuador – including Galapagos Islands, El Salvador, Guatemala, Honduras, Indonesia, Japan, Malaysia, Mexico, Nicaragua, Panama, Peru,  Philippines, Republic of Korea, Russian Federation, Singapore, Thailand, Timor-Leste, United States of Americaincluding States, Territories of American Samoa and Guam, Commonwealth of Northern Mariana, Islands, and US Minor Outlying Islands (Baker, Howland, Jarvis, Johnston, Kingman Reef, Midway, Palmyra, Wake), Vietnam


Australiaincluding Territory of Norfolk, Coral Sea, Cook Islands (free association New Zealand), Fiji, France – French Polynesia, New Caledonia,Wallis and Futuna, KiribatiGilbert, Phoenix, Christmas, Marshall Islands (free association USA) – Kwajalein, Majuro *, Micronesia,Federated States of (free association USA) * – Chuuk, Kosrae, Pohnpei, Yap, Nauru *, New Zealandincluding Kermadec Islands, Niue (free association New Zealand), Palau (free association USA), Papua New Guinea, Samoa, Solomon Islands, Tokelau, Tonga, Tuvalu, UK – Pitcairn, Vanuatu


The IOC maintains the International Tsunami Information Centre (ITIC). Established in 1965 and staffed by the U.S.A., Chile, and Japan, the ITIC works closely with NOAA’s Richard H. Hagemeyer Pacific Tsunami Warning Center (PTWC), and other international tsunami centres such as Japan's Northwest Pacific Tsunami Advisory Center (NWPTAC) and NOAA's US National Tsunami Warning Center (NTWC).

ITIC's primary responsibilities also include:

  •  monitoring the international tsunami warning activities in the Pacific and other oceans and recommending improvements in communications, data networks, acquisition and processing, tsunami forecasting methods, and information dissemination;
  • bringing to Member and non-member States information on tsunami warning systems, on the affairs of IOC and ITIC, and on how to become participants in the global TWS;
  • assisting Member States in the establishment of national and regional warning systems, and the reduction of tsunami risk through comprehensive mitigation programmes;
  • acting as a clearinghouse for the development of educational and preparedness materials, event data collection, and the fostering research and its application to prevent loss of life;

The PTWC serves as the operational warning headquarters for the Pacific Tsunami Warning and Mitigation System. PTWC works closely with other international, sub-regional and national centers in monitoring seismic and sea level stations around the Pacific Ocean for large earthquakes and tsunami waves. The PTWS makes use of about 600 high-quality seismic stations around the world to locate potentially tsunamigenic earthquakes, and accesses about 500 coastal and deep-ocean sea level stations globally to verify the generation and evaluate the severity of a tsunami. The system disseminates tsunami information and warning messages to designated national authorities in over 100 locations across the Pacific. Sub-regional centres such as the US NTWC and NWPTAC provide regional alerts to the U.S.A. west coast, Alaska and Canada, and the northwest Pacific and South China Sea regions, respectively.

The Pacific Tsunami Warning and Mitigation System is one of the most successful international scientific programmes with the direct humanitarian aim of mitigating the effects of tsunami to save lives and property.

For further information, contact,

PTWS Organizational Structure PDF (367 KB), Mar 2014

ITIC Organizational Structure PDF (319 KB), Mar 2014


Table updated 20 July 2012



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